DevSecOps workflows with conditional CI/CD pipeline rules

What this post added

This post introduces and explains the `rules` feature in GitLab CI/CD, detailing its various keywords (`if`, `changes`, `exists`, `allow_failure`, `variables`, `when`, `needs`) and their practical applications. It demonstrates how to control job execution based on CI/CD variables, file changes, existence of files, and workflow conditions. It also provides use cases for enhancing developer experience and integrating security and quality assurance checks. This post expands on the existing `gitlab-ci-and-distributed-builds` thread by focusing on the conditional execution of jobs within pipelines.